This is a continuation of cooperative study of chemotherapy of cancer in children by Children's Cancer Study Group A. Currently, there are five protocol studies involving patients with leukemia and eight studies for solid tumors. The principle ALL/AUL leukemia protocol is designed to evaluate four alternative regimens to prevent CNS and other sanctuary relapse by giving either radiation or intrathecal methotrexate on both after the initial remission induction. A specific protocol study is available for patients with Wilms' tumor, localized and metastatic rhabdomyosarcoma, localized neuroblastoma, Histiocytosis X, osteogenic sarcoma, Hodgkin's Disease.